1. Field of the Invention
The present invention relates to an optical scanning apparatus, and, more particularly, the present invention relates to an optical scanning apparatus including a bar code reader used in a point-of-sale (hereinafter "POS") system capable of reading the bar code information attached to commodities and performing check-out functions.
2. Description of the Related Art
In recent years, the use of the POS systems capable of performing the check-out functions by reading the bar code information attached to commodities has become widely available. These POS systems alleviate the load on operators by simply requiring the operator to handle the commodity at check-out so that the bar code is read by the scanner. The apparatus for reading this bar code information is referred to as a POS scanner or bar code scanner. The scanner portion of the POS scanner normally employs a laser beam and is attached to the checkout counter.
Conventionally, the scanner is configured so that a single reading window is installed horizontally on the counter surface. However, recent trends in POS scanner design have employed two distinct designs which were developed to meet customer demands. The first has found significant acceptance especially in the United States and uses a multi-head scanner having glass windows located on both the side and the bottom of the apparatus from which laser beams are emitted in order to read the bar codes. Using this design the operator's workload is even further reduced since either the scanner embedded in the counter surface reads the bar code or the side scanner reads the bar code.
In Japan and Europe the demand for cheaper scanners exists and the high-performance scanner described above using two reading windows have generally not been used. Instead, the conventional POS scanner apparatus is installed in a vertical position with respect to the counter and thereby enabling the smooth movement of commodity packages. However, user demand for an even less costly scanner which is easier to use always exists.
Commodities packaged and arranged in stores include liquid items, such as beverages and soups, as well as fragile commodities, such as cakes. If these types of commodities are tilted when scanning the bar code, the risk exists that the liquid would spill and smear the check-out counter or the commodities are deformed which would adversely affect their appearance.
All the conventional POS scanning devices in the prior art have the problem of requiring tilting commodities being scanned. In addition, the vertically-installed scanner used in Japan and Europe uses only one reading window and therefore the range of bar code orientation allowed for reading is limited.
In the conventional apparatus having reading windows in both the counter surface and the front thereof, the scanner acts as an obstruction to the movement of commodity packages. Therefore, this apparatus has rarely been introduced in the stores in Japan. In all of the conventional POS scanners, the operator must place the bar code surface toward the window face. Therefore, the operator is unable to handle the commodities while watching the bar code.
FIG. 8(a) is a diagram showing an optical scanning apparatus disclosed in U.S. Pat. No. 5,229,588 as an example of a conventional optical scanning apparatus. This apparatus is so designed that the laser beam emitted from a laser light source 1 is scanned by a polygon shaped mirror 2 and reflected by mirrors 3 and 4 so that a laser scanning pattern A is emitted from a window 5 positioned substantially vertical thereto. At the same time, a laser scanning pattern B is emitted from a horizontal window 6 embedded in the counter surface through a mirror which is not shown in the diagram.
Another POS scanner known in the art is shown in FIG. 8(b) as disclosed in JP-A-63-192175. This apparatus comprises a commodity sliding surface 7 and scanning windows 8 and 9. Window 8 is located on the commodity sliding surface of the counter and window 9 is located above the sliding surface. Laser scanning pattern A is emitted through window 9 and laser scanning pattern B is emitted through window 8.
A still further example of the conventional POS scanner is shown FIG. 8(c) as disclosed in U.S. Pat. No. 5,140,141. This apparatus comprises a reading window only above a commodity sliding surface 7 and is so configured that a laser scanning pattern A is emitted from the window.
Another example of a optical scanning apparatus (not shown in any drawing) is disclosed in U.S. Pat. No. 5,206,491. This apparatus comprises reading windows on two sides thereof, and the laser beam(s) emitted from these windows either using two laser light sources or one laser light source split into two portions by a beam splitter. The resulting two beams are read by the optical scanning apparatus.
Problems encountered in a conventional apparatus as disclosed by U.S. Pat. No. 5,229,588 exist due to the scanner section being located on the counter surface and forming an obstruction to the movement of commodity packages. Also, in order to scan a package, tilting the commodity is required which prevents the operator from viewing the bar code at the same time. Further, as shown in FIG. 8(a), although the laser beam entering the optical scanning device 2 from the laser light source 1 is substantially perpendicular to the rotational axis of the optical scanning device, scanning from the optical scanning device (in the direction toward the mirror 3 from the scanning device) is not perpendicular to the rotational axis but titled slightly upward. Under this configuration, if the scanning beam A reflected by the mirror 4 and emitted through the window 5 is to be scanned in the direction substantially parallel to the window 6, mirror 4 must be tilted to accomplish this. When the apparatus disclosed by U.S. Pat. No. 5,229,588 is installed vertically, the size of the upper optical section increases to the point that problems are encountered in use.
In the example of the conventional apparatus provided in JP-A-192175, the scanner section on the counter surface forms an obstacle to the movement of packaged commodities. In addition, the apparatus of JP-A-102175 having three sections including a counter surface, a side section and a top section, is complicated and expensive.
In the third example of the conventional apparatus shown in U.S. Pat. No. 5,140,141, several advantages are seen including: not requiring the tilting packaged commodities; the operation being possible while the operator watches the bar code; and that there is no obstruction to packaged commodity movement. However, a problem exists in that the laser beam is emitted only in one downward direction resulting in a narrow allowable legible angle of the orientation of the bar code. This problem can be alleviated by increasing the size of the device but would increase the cost of the support member for the scanner and would also adversely affect commodity handling. Therefore, the allowable size of the configuration of the apparatus is unavoidably limited.
The fourth example of conventional devices as disclosed in U.S. Pat. No. 5,206,491, the problem of high cost is encountered. This high cost is due to the configuration requiring two laser beams being emitted or one using a beam splitter to create two beams along with the two beams being introduced to the optical scanning device.